Final answer:
The noun phrase in the sentence is 'The dog on the couch'.
Step-by-step explanation:
The noun phrase in the sentence is The dog on the couch. A noun phrase is a group of words that functions as a noun in a sentence. In this case, 'The dog on the couch' is a noun phrase because it consists of a determiner ('The') and a noun ('dog') along with a prepositional phrase ('on the couch').
Learn more about Noun phrases in English sentences